Tag: cosmic rays

One thing I like to see is kids getting their hands on doing science. There’s something about being involved with something, actually doing it for yourself, that gives you a sense of ownership over the knowledge, makes you part of something bigger.

Here’s another chance to do that for students across the world: the ERGO telescope project. ERGO stands for "Energetic Ray Global Observatory" and the idea is to build simple cosmic-ray detectors that can be sent to classrooms all over the world. Here’s a short video describing the project:

Cosmic rays are energetic subatomic particles that come blasting in from space. They’re created by the Sun, by exploding stars, but distant galaxies… basically, by cool, interesting objects. By distributing these detectors across the world, students can share their data and come up with their own ways of examining them.

There’s only one problem: that’s completely wrong. In reality the study shows nothing of the sort. The evidence, as far as the limitations of the experiment go (that’s important, see below), do not show any effect of cosmic rays on global warming, and say nothing at all about the effect humans are having on the environment.

What did you do, Ray?

OK, first things first: why should we even think cosmic rays might affect climate? There are several steps to this, but it’s not too hard to explain.

We know that clouds form by water molecules accumulating on seed particles, called condensation nuclei. The physical processes are complex, but these particles (also called aerosols) are suspended in the air and water droplets form around them. The more of them available, the better water can condense and form clouds (although of course this also depends on a lot of other things, like how much water is in the air, the temperature, the height above the ground, and so on).

Cosmic rays, it turns out, may play a role in this too. They are subatomic particles that zip through space at high speed. We are bombarded by them all the time, in fact! They hit atoms and molecules in the Earth’s atmosphere, depositing their energy there. This affects aerosol formation rate, and therefore might affect cloud formation. Clouds are bright and white, and reflect sunlight. Therefore they affect global warming.

So the whole idea goes like this: the more cosmic rays there are, the more aerosols are made, the more easily clouds can form, the more sunlight gets reflected back into space, and the less global warming we get. It’s controversial, for sure (Discover Magazine interviewed a proponent of this idea in 2007) but worth looking into.

ConCERNing clouds

In practice, the actual connection between cosmic rays and cloud formation is really hard to determine. So a group of scientists at the European particle lab CERN decided to test the basics. They created a cloud chamber, bombarded it with cosmic rays, and examined the results. They found two very interesting things:

1) The number of aerosols created went up vastly as the particles blasted the chamber. That would seem to indicate that cosmic rays really are tied to global warming. Except…

2) The actual total number of aerosols created was way below what’s needed to account for cloud formation. Sure, there were more aerosols, but not nearly enough.